


i didn't mean to try you on

by derogatory



Category: IDOLiSH7 (Video Game)
Genre: Anal Sex, Dirty Talk, M/M, Masturbation, Sibling Incest, Voyeurism
Language: English
Status: Completed
Published: 2018-09-25
Updated: 2018-09-25
Packaged: 2019-07-17 12:44:20
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,649
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16095926
Author URL: https://archiveofourown.org/users/derogatory/pseuds/derogatory
Summary: Tamaki or Riku are much more appropriate people for Iori to think about when it comes to sex. Much better than his brother.But...





	i didn't mean to try you on

Iori stands at his brother's bedroom door, stock still and silent, listening carefully. 

Living in the dorm had been difficult at first, but Iori feels he's adjusted adequately. After all, having grown up with a sibling, he's used to sharing spaces; he and Mitsuki's rooms had always been next door to each other. He often remembers the times when he'd have a nightmare and Mitsuki would slink into his room, would stroke his hair and sit with him until he fell back asleep.

 _I heard you crying through the walls,_ Mitsuki would say as Iori drifted back to sleep, comforted by his brother's presence.

It's been years since then, but Iori recognizes the voice through the wall. He grew up listening to Mitsuki's pitches and sighs. He literally knows that sound in the dark. 

_Brother must be having a nightmare,_ he thinks and turns the doorknob slowly. It's been a long time since Mitsuki came into his room in the middle of the night to comfort him, but he treasures those sweet memories. It might be nice to do the same for Mitsuki.

The sound Iori had heard was strange, but the sight that greets him — the sight is stranger.

He sees Yamato on his back in Mitsuki's bed. That's strange enough, but then again Yamato has a reputation for getting sloppy when he drinks too much. And Mitsuki's a good friend, an excellent caretaker, so that could explain what Yamato's doing there. 

Less easy to explain is Yamato's bare chest, lurching with breath, and his head tossed back against Mitsuki's pillows. Iori sees all this in a slow-motion as the rest of the dark room comes into focus. The strong line of his brother's shoulders, the sculpted muscles of Mitsuki's back that faces the door. The soft hair at the nape of Mitsuki's neck. His hands around Yamato's thighs and his hips, thrusting forward, into the other man—

Iori freezes. 

He shouldn't be here, he shouldn't be seeing this — whatever _this_ is. Of course, Iori knows what it is, he's not a child. He knows all about these kinds of things! But as close as he and Mitsuki are, they’ve never been the kind of brothers who confide in one another about their sultry affairs. Not that Iori had any to tell! But still, it isn't something they talk about. And it certainly isn't something Iori should think about. He lets that part of Mitsuki's life stay private, away from him. That door is locked and barred and Iori resolutely avoids thinking about his brother and that kind of thing. It's abnormal, deviant.

And yet...

And yet this door was open. 

It’s _still_ open as Iori stands frozen in place and watches Mitsuki lean over Yamato. Iori’s brother rolls his hips and Yamato breathes in a tense, almost pained, hiss. _Does it hurt?_ Iori wonders, peering through the dark. Would it hurt to have Mitsuki closer than he’d previously ever thought possible, to have his brother's hands clamped down on his hips, pulling Iori to the edge of the bed...

Iori blinks rapidly, trying to clear his thoughts. No, that's wrong. He doesn't think about this kind of thing. He doesn't. He shouldn't. Not about Mitsuki, not about anyone doing those things with his brother, especially not _Yamato_.

Because really, if Iori thought anything about it at all, he would've assumed Mitsuki and Yamato were just friends. Good friends, sure, close friends. The sort of friendship Iori hopes he might have with someone one day. A hope he has when Riku looks at him with too bright eyes and talks about their future, or when Tamaki falls asleep on his shoulder on the train.

Right, Tamaki. Tamaki or Riku are much more appropriate people for Iori to think about when it comes to sex. Much better than his brother. Even thinking about Yamato would be fine, or literally thinking about anyone else in his life. Maybe even Manager (although that thought seems much too lewd.) These would all be better people for Iori to visualize when he thinks of _it_ , much better than imagining his brother crouched against the sheets, naked skin gleaming with sweat.

But…

From this angle, he can see the outline of the muscles of Mitsuki's thighs. _Oh_ , Iori thinks vacantly. He hasn't seen those muscles in a while. _Not since the last time they put Brother in shorts._

Hot shame washes over Iori for every millisecond that passes where he doesn't shut the door and hurry away. After all, he can't be held accountable for stumbling in on something like this. This kind of mix-up was bound to happen eventually; communal living, after all. And Iori had been incredibly naive, thinking those sorts of sounds from his brother were ones of distress. It's stupid, imagining Mitsuki needing help from him. Mitsuki takes care of Iori; he's the older brother after all. It had been foolish to assume Iori could look after him, even just once. It was stupid to think about kneeling at his bedside and sweeping the hair off Mitsuki's forehead. _Brother, I'm here,_ he'd say and Mitsuki would come back to waking in soft, incremental motions. Gaze up at Iori adoringly, so quiet and gracious and good and wonderful.

 _I'm here for you,_ Iori would say and cup Mitsuki's cheek with his hand. And his brother would rest a hand over his, trace it along Iori's skin, before reaching out and tugging Iori into bed with him. They've shared a bed many times, countless times when young Iori crawled into Mitsuki's futon and cuddled with him in the dark. It would be nothing new to crowd their bodies together; his legs grazing Iori's, the hair there tickling against his sensitive skin. Mitsuki would sigh and press his face to the spot between Iori's shoulder and neck. His breath warm on his neck as he’d inch closer and closer, hands tightening around Iori's waist—

Except that isn't what happened! Nothing like that would ever happen. Instead what really happened was Iori walking in on Mitsuki doing something extremely private, and Iori standing here, watching like some sort of a pervert. Prying in on this intimate moment instead of running away. Of course, Iori still plans on eventually running away. He'll leave and neither man will need to know that Iori is some deviant. Iori will close the door right this second, this instant. 

It's just... 

Iori's gaze travels to Yamato because that's safer than looking at his brother, than listening to the sweet sounds spilling from Mitsuki's mouth. It's much more acceptable to look at Yamato's face, lips parted, eyes closed. He's never seen Yamato make that face before; he's always so cool and collected. Now he looks overwhelmed, wrought with the sensation of Mitsuki working into him.

Then again, of course he is. Mitsuki is a very generous person, he always puts the needs of others first. Of course Mitsuki would be the same when he — during — in _bed_.

A bead of sweat trails between Mitsuki's shoulder blades. Iori's throat is very dry.

Yamato's hand caresses its way up Mitsuki's body, cupping his palm against his cheek. An open flame of jealousy licks at Iori’s heart. When Mitsuki turns his face to kiss into that palm, Iori sees a sliver of his face: open, playfully affectionate. Confident in this secret moment between them.

 _I want to see more,_ Iori thinks, wretched. He leans his weight against the door just slightly, opening it wider. 

It creaks.

Luckily, Mitsuki doesn't seem to notice, the noise hardly breaking his stride. Iori breathes a sigh of relief. He must be caught up in the moment, Iori thinks, heart swelling with fondness. Brother must be really happy with Yamato, the two of them lost in each other's arms— 

No, not two of them. Because Yamato is looking at Iori.

Iori goes from feverish hot to icy cold. Yamato stares, eyes white in the dark of the bedroom. Iori is pinned to the spot, like an insect to the wall.

Yamato blinks, slow and easy. Iori doesn't dare breathe. He's been discovered but... Yamato still isn't doing anything. Which is impossible, Yamato would never miss an opportunity to tease him. Maybe this is too far, beyond teasing. Maybe Iori spying on them like this is too serious for even Yamato's good-natured pestering. Bile rises in Iori's throat at the thought of what surely must happen next; Yamato, sitting up and drawing Mitsuki's attention to his brother's crime. Mitsuki's wide-eyed, hurt look. _I'll have to leave the dorm_ , Iori thinks, sick with regret. The dorm and maybe Idolish7 as well. What will he tell Manager? What will he tell their parents?

Yamato squints.

A wave of relief cascades over Iori. Of course! Yamato isn't wearing his glasses. He isn't able to see anything from that far away. Iori gratefully sucks air back into his lungs. Surely Yamato can't tell what he's looking at; he wouldn't be able to identify Iori in the dark. Iori's shameful secret is safe for now, provided he finally tears himself away to retreat to his room.

Iori gently pulls the door towards himself in small, barely noticeable motions. Now he can slip away and keep this dark moment to himself.

And then, like the master actor he is, Yamato whines, "Oh, _Mitsu_." and Iori realizes he's definitely been spotted; Mitsuki might not have realized but Yamato absolutely does, is looking right at Iori in the doorway. "That feels so good..." His voice is at an exaggerated pitch, breathy and, as far as Iori is concerned, unnecessarily rude. Iori’s stomach churns in humiliation, stunned still. There's no denying their leader can see him as Yamato tosses his head back and moans, "Yes, fuck me."

"You're noisy today," Mitsuki says. His brother's voice makes Iori's blood burn under his skin. Mitsuki sounds a little out of breath. How long have they been doing this? How long does it usually last? 

"Yeah?" Yamato's not looking at the doorway anymore but, furiously, Iori can tell these awful comments are directed to him. "Or maybe I just can't get enough of Mitsu's big, fat cock."

Iori reels. How disgusting! That's obscene, Yamato should know better than to say something so dirty. Even if he and Mitsuki are… even if they're…

But Mitsuki just laughs. 

"Okay," he says with a hint of a smile in his voice. Iori's startled by the way his body responds to it, aching forward. "I can tell you're making fun of me, but I'm kinda into it."

Yamato hums thoughtfully, hand tracing along the back of Mitsuki's neck. "Maybe you should shut me up."

"Yeah," Mitsuki murmurs, low and heated, and Iori finds himself inexplicably keening towards it. "All right."

Mitsuki pulls away from Yamato — or rather he pulls out, and all at once Iori sees it: his brother's cock, flushed and swollen. Iori knows he needs to stop or look away. He needs to go back to his room, or at the very least sit down before all the blood rushes from his head.

In one fluid motion, Mitsuki reaches forward and flips Yamato over, shoving his face into the mattress. And Yamato's shout of surprise is funny enough that Iori might have been amused... if he wasn't so turned on. Iori rubs the heel of his hand against his pajama pants and bites back a moan. He sees stars even just touching himself through the fabric, and he lets out his breath in a harsh exhale.

Once he's willed himself to be silent, he opens his eyes. Mitsuki's hand rests on the small of Yamato's back, braced against him, holding him still as Mitsuki slides back inside. Yamato's ass takes him, slick and easy, as Yamato groans.

"Ah, Mit...su..." he says, head to the side, open-mouthed panting against the blankets. Iori is scalding hot, rutting against his hand as the sound of wet bodies together match the pound of his heartbeat. He turns to rest his own face against the doorframe, the wood oddly cool against his skin. He's helpless to everything around him; the slap of hips together, Mitsuki's small hisses of satisfaction, or the throbbing need between his legs. 

Iori braces his heart and hopes one day Mitsuki will forgive him for the way his hand slips past the waistband of his shorts.

"You quieted down," Mitsuki mumbles, barely audible over the staggeringly good feeling of Iori wrapping his fist around his cock. If he keeps his eyes locked on his brother's face he can even imagine Mitsuki is actually talking to him. "You loved it."

"Ah..." Yamato grimaces at a particularly deep thrust, more brutal than Iori ever imagined Mitsuki could be. Iori's knees feel weak. He wants to see more, he wants it. He needs to feel it. Breathless, Iori swipes his thumb over the tip of his cock and bites back a moan. He needs this, he needs Mitsuki touching him, inside him. He can't imagine anything else but the overwhelming need to be the one Mitsuki's laid over the bed.

"Wait," Yamato says, voice ragged. Iori feels a slap of cold water remembering that they're not really alone, that Mitsuki isn't the one speaking to him — that Yamato can _see_ him!

Yamato reaches back, gingerly trying to detangle himself from Mitsuki. "I want to see you," he says, eyes dazed and uneven. Of course they are; Mitsuki is so talented, naturally he'd be great at se… at... at something like this.

Separated from Mitsuki, Yamato sits up uneasily on his hands and knees. Slowly he slakes eyes on Iori, who's still leaking precome all over his own knuckles. All the oxygen is sucked out of the room at the realization that at any moment Mitsuki could lift his head and look where his partner is looking. Mitsuki could spot Iori, shamefully jerking off to his brother's sex life, ruining everything between them.

Yamato offers Iori a small grin in the dark and turns around. "Hey Mitsu," he says, focusing Mitsuki's attention away from the doorway. "Lay down."

"What?" Mitsuki says, hesitantly arguing, "Ah, no, I want to—"

"Trust me." Yamato reaches for him, and Mitsuki goes, resting at the foot of the bed. Mitsuki tips his head back, his chin is pointed to the ceiling, his gaze traveling the length of the room...

"No," Yamato's voice rings out, stern and commanding. "Look at me."

Mitsuki looks away from the doorway just in time and offers Yamato a toothy smile.

"You got it, Leader."

Yamato huffs a little as he climbs onto him, straddling Mitsu's hips with his own. Iori swallows back a lump in his throat. From that angle he can see his brother's dick again, standing at attention, red and leaking and a fraction of an inch away from Yamato. Iori squeezes his cock until there are spots behind his eyes. He shouldn't be here, he shouldn't be looking, he shouldn't be so desperate to have it be his hole sinking onto Mitsuki.

Those filthy thoughts must be written all over his face. His face that Yamato keeps staring at as he drops onto Mitsuki's dick. Iori lifts his free hand to his mouth to cover a blissful sigh at the sight of it; Yamato's body enveloping Mitsuki. His hole stretches around Mitsuki's length, takes it inside him slow and familiar. Yamato's face is pink high on his cheeks, panting as he lowers himself, muscles clenching around Mitsuki's perfect dick.

 _Brother is always so kind and generous._ Iori thinks, deliriously rubbing his cock, spreading its wetness from tip to base. Maybe Mitsuki wouldn't even mind that he's watching them. Iori whimpers as the two on the bed shift positions, Mitsuki planting his feet against the mattress for leverage. _Maybe it's not so bad to watch a little more._

Still looking only halfway adjusted to Mitsuki's full length inside him, Yamato pauses, his mouth twisting in a way Iori recognizes. That's their beloved leader's expression just before he says something snide. He could really do without his attitude right now. If Yamato actually wanted to expose Iori, he'd have done it already. He must not really care that Iori is watching. How much can he really love Mitsuki if he's willing to share?

 _If it were me,_ Iori thinks and his insides lurch as a powerful point pulses below his waist. _If it were me I'd never let anyone get between me and Brother._

Iori bites the inside of his mouth hard, trying not to cry out. Luckily it's not really necessary, as Mitsuki chooses that moment to thrust hard into Yamato, causing the other man to shout. Yamato lurches with the motion, head thrown back, shoulders shaking.

"O-oh…!" His fingers scramble along Mitsuki's bare chest, the sculpted muscles of his abdomen. He struggles to find something to brace himself on, to ride out the unbearable pounding of the body beneath him. "Mm…" 

"You like that?" Mitsuki asks on a hushed breath, hands clamped around Yamato's waist to hold him in place. He grinds into his ass and Yamato hisses, quivers lancing through him.

"Ah, Mitsu," Yamato manages to say, voice trembling from how hard Brother's thrusting into him. The room swims around Iori; his vision going blurry at the edges. "T...Touch me…"

As Mitsuki wraps his hand around Yamato's cock, Iori hurriedly tries to sync up his motions. Touching himself like this… It feels so good, like sinking into a dream. _Brother is so giving. Brother is so good at sex. Brother could throw me down on this bed and drill me until I was dead and I'd_ thank _him for it._

"Yes," Yamato sighs, rolling his hips in tandem with Mitsuki's moves. "Yes, Mitsu…" He swallows hard. "Y-You're so good, you're so big— ah.."

"What?" Mitsuki laughs. "You're being really weird today." But it doesn't seem like he's complaining. Suddenly they're rearranging their positions again; Mitsuki sits up and Yamato grunts in pain. That new angle must hurt. Mitsuki runs his hands over Yamato's broad shoulders, sitting up enough he can plant soft, hurried kisses around Yamato's mouth. Shame gnaws at Iori's frayed edges, watching these private moments. Yamato takes a few shuddering, gulping breaths, acclimating to the new angle. Mitsuki clutches him close in his lap, kisses slowly becoming less comforting, more sensual, tongue slipping into that gasping mouth.

"You okay?" Mitsuki asks quietly and Yamato nods once, then again, more urgently. He leans in and Mitsuki gasps too- something about that angle must feel good for him as well. Iori aches for it, jealous someone else can make Mitsuki so happy. 

"So... good," Yamato mumbles, and Iori watches his fingers scrape against Mitsuki's back. "Fuck me harder."

"Okay," Mitsuki says and Iori can hear his brother's smile. "If you say so." He rolls his body forward and Yamato cries out. Iori desperately thrusts into his palm, dripping wet over his fingers.

"Does that feel good?" He hears Mitsuki murmur.

"Yes," Iori whispers, eyes screwed shut. 

"Do you want to come?"

"Please," Iori sobs, burying his face into his shoulder and painfully wishing the questions had been for him.

Across the room, Yamato makes, small vulnerable sound Iori doesn't recognize. It momentarily quells his self-pity and arousal; Brother is so strong. What if he hurt Yamato?

Watching them, he can again only see Mitsuki's back, the steady lines of his shoulders as his hands smooth down Yamato's hair. Yamato's forehead is damp with sweat, his eyes are shut tight. He's shaking but Brother isn't hurting him; Mitsuki is too careful for that. It must feel so good it's overwhelming, so good Yamato can't keep up his teasing. Iori's happy he doesn't have to contend with Yamato's meanness for the moment, but it's a small victory when it's not _him_ Mitsuki is touching!

Iori rocks into his hand, trying to imagine how it would feel to have Mitsuki all over him, his cock buried deep inside Iori's body. It'd be too good. There's no way he'll be able to think about anything else again now that he's seen it up close. Perfect Brother and his perfect cock giving Iori such incredible pleasure… Iori is dizzy with it. He probably wouldn't deserve it, but let's be real; like Yamato's done anything to make himself worthy of Brother's affection.

Yamato's eyes open, locking his gaze with Iori again, almost like he’d heard. He's breathing hard, chest heaving; quiet and calculating. 

His hips jerk and Yamato holds back a stifled moan as Mitsuki grinds against him, growling something inaudible in his ear.

"Yeah," Yamato pants, shivering. "Yeah, do it. Fill me up, big brother."

"Wait, what?" Mitsuki turns to him in surprise. "What the hell — Ah...!" Mitsuki's confusion turns to pleasure, shaking with the force of his orgasm, emptying wild and hot into Yamato. Yamato sinks his mouth against Mitsuki's shoulder, stiffening in similar ecstasy. 

Iori knows he should be more embarrassed- it should be humiliating that Yamato got one last dig in. But Mitsuki's voice, breaking as he comes, and the way Yamato must have felt filling up with his brother's — with Mitsuki's… 

Iori shudders and comes with a groan, curling in on himself. White hot satisfaction is followed immediately by the cold touch of guilt, desperate and shameful. He really — he actually came from watching Brother…!

Iori finally manages to pry his eyes away, slamming the door to their room in a panic. On the dash back to his room, he can hear his brother's raised voice and Yamato's smug laughter. Iori's face is burning hot as he throws himself into his own bed. A part of him hopes he can convince Mitsuki it had just been an accident, that he hadn't really seen anything.

Another part of Iori, dark and sinister, hopes next time Mitsuki will let him watch from inside the room.

**Author's Note:**

> heh
> 
> follow me @ mobchuu on twitter!


End file.
